DNSdumpster.com is a FREE domain research tool that can discover hosts related to a domain. Finding visible hosts from the attackers perspective is an important part of the security assessment process.

Compare the speed of enterprise and commercial DNS services

“DNSYO is a little tool I built to help me keep track of DNS propagation. In short, it’s nslookup, if nslookup queried over 1500 servers and collated their results.”

Wildcard DNS - useful for local mobile testing. e.g. 10.0.0.1.xip.io resolves to 10.0.0.1

Full DNS control and setup guides for popular web services like Tumblr

JSONP RESTful interface for DNS lookups

Free DNS, Static DNS, Dynamic DNS, URL Redirection